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Article
Publication date: 5 October 2015

Fairuz Romli and Mohammad Yazdi Harmin

– The purpose of this paper is to achieve the capability of redesigning complex products system with enhanced efficiency and effectiveness.

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Abstract

Purpose

The purpose of this paper is to achieve the capability of redesigning complex products system with enhanced efficiency and effectiveness.

Design/methodology/approach

It is noted that, by changing one subsystem in a complex product design architecture, the change effects can be propagated to other subsystems through their interrelationships. This condition has to be taken into account when deciding on which subsystems to be modified in the redesign plan because the subsequent effects might be too risky for the development process. Estimating redesign risk for complex product architectures is not an easy task, thus designers often need a decision-making aid to efficiently select the best “change initiating” subsystems. This can be done by providing the designers with a ranking of subsystems based on their estimated redesign risk. Moreover, this decision-making process is taking place during early redesign stages whereby the uncertainties related to the actual level and type of changes to be made on the subsystems are high. Because of this, a stochastic approach is taken to be more appropriate in deriving the redesign risk estimates. This leads to the proposed application of the Monte Carlo method to estimate the subsystem redesign risk for complex products, as demonstrated through an example case study of aircraft redesign.

Findings

This use of the Monte Carlo method helps to distinguish the level of risks associated with each subsystem in the complex product design architecture, which is helpful for designers while making decisions on which subsystems to be changed for the redesign task at hand.

Practical implications

This technique can be applied to assist designers in making decisions during the early stages of the redesign process under high design uncertainties.

Originality/value

The work presents a new alternative method to estimate the redesign risks of subsystems in complex products that can improve the effectiveness of the designer’s decision-making process in the early redesign stages. While many other available change methods tend to ignore the uncertainty associated with the decision-making process, the method presented here directly takes into account the stochastic nature of the process.

Details

Aircraft Engineering and Aerospace Technology: An International Journal, vol. 87 no. 6
Type: Research Article
ISSN: 0002-2667

Keywords

Article
Publication date: 5 October 2015

Aaron Aw Teik Hong, Renuganth Varatharajoo and Fairuz Romli

The purpose of this paper is to develop analytic solutions for a tethered satellite system (TSS) subjected to internal tether tension moment and external aerodynamic torque for…

480

Abstract

Purpose

The purpose of this paper is to develop analytic solutions for a tethered satellite system (TSS) subjected to internal tether tension moment and external aerodynamic torque for spin-up and spin-down manoeuvres.

Design/methodology/approach

Analytic solutions for TSS based on the approximation of Euler’s equations of motion via Fresnel integrals and sine and cosine integrals. Test simulation was performed for two cases (spin-up and spin-down manoeuvres). The conclusion is based on graphical interpretation.

Findings

The effects of angular velocities on X, Y and Z axes of the TSS under the influence of combined torques from internal tether tension and external aerodynamic drag influenced during spinning manoeuvres are shown graphically.

Research limitations/implications

This research focuses only on a circular orbit, which is one of the simplest orbits without many variables taken into account such as flight path angle and true anomaly. It could get quite complex for other orbit types like elliptic and parabolic orbits.

Practical implications

Practical implications include observing the stability rotational motion of TSS so as to perform a two-way payload exchange via momentum transfer.

Originality/value

In this paper, analytic solutions for a torque motion of a TSS comprising non-linear Euler’s equations of motion are established for spin-up and spin-down manoeuvres.

Details

Aircraft Engineering and Aerospace Technology: An International Journal, vol. 87 no. 6
Type: Research Article
ISSN: 0002-2667

Keywords

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